BOULDER, Colo. — The Chinook helicopter landed, the hatch opened and about rescued 20 school children walked out the back.

The children, each about 10 years old, had been plucked from the Cal-Wood Education Center, a camp at 7,800 feet in the Arapaho-Roosevelt National Forest about 15 miles outside of Boulder. They walked with springs in their steps as they got off the large helicopter.

Just minutes earlier, a woman walked out of another helicopter and immediately hugged each of the search and rescue workers who had just delivered her to safety.

All day Saturday, heart-warming scenes of people touching dry, safe ground — some for the first time in two or three days — repeated itself at the Boulder Municipal Airport.

A half-dozen Chinook and Blackhawk helicopters continuously picked up stranded residents Saturday who were trapped in the mountain towns of Lyons, Jamestown, and other nearby communities where ground access was no longer a possibility because of washed out and destroyed roads and bridges.

Colorado officials on Saturday said they believe it is the largest rescue operation of Americans by helicopter since Hurricane Katrina.

But while Saturday's effort was on picking up people off the mountains who were in obvious need of rescuing, the transition into more of a search effort — and possible recovery effort — was expected to start Sunday.

That's where members of Utah Task Force 1 come into play.

The 80-member team set up camp at the Boulder Municipal Airport Friday night, along with fellow urban search and rescue teams from Nebraska and Colorado. When their time comes, their job will include being dropped off by helicopter into the flood-ravaged areas and going to each home to look for people who need assistance, or for possible bodies.

The Colorado National Guard and a unit from Fort Carson, an Army base near Colorado Springs, have rescued an estimated 1,200 people since Friday, according to National Guard officials.

About 20 of those rescues were conducted using a hoist from the helicopters. Approximately 500 of those residents were rescued by National Guard troops on the ground. In addition, approximately 200 pets had been rescued in Boulder County since Thursday.

The crew from Fort Carson, who earlier this year assisted with fighting Colorado's wildfires, used night vision technology to continue the rescue operation around the clock. An equal number of helicopters conducted similar rescue operations to the north in Larimer County.

Pelle called the rescue mission Saturday as an "intense operation in the air on a level I've never seen."

Kathryn Stanford and her friend Courtney Avery had been stranded near Nugget Hill in the Jamestown area since Thursday. All the roads were waterfalls and the bridges wiped out.

"It's awful. It's a rushing river basically on the road," Stanford said.

Saturday morning, they were picked up by a Chinook helicopter.

"I just want to see my family, that's all I care about right now," she said before having a tearful reunion with her father. "Our family and friends have been worried sick, so I just want to, like, give them the biggest hugs in the world.

"It just makes you realize how fragile life can be. You never know if you'll be given a tomorrow."

One of the people rescued was a pregnant woman whose due date was this weekend. She was airlifted out of Lyons Friday during the day, and her water broke that night.

"There are some personal stories coming out of this that makes all of this very, very rewarding," Pelle said.

Three people were confirmed dead in Boulder County as of Saturday, the sheriff said. Statewide, there were reports of five dead from the flooding. Pelle hoped that number wouldn't go up, but couldn't say for sure how things would turn out.

"I'm hopeful, I pray that that's all there is. The cautionary note is this: we have not begun to search collapsed structures, debris piles and wash-outs where we would likely find human remains. And so, I don't want to be pessimistic, but I also want to be realistic about the probability that we will find others. I pray not, hope not. But that's the reality of the situation," he said.

The members of Utah Task Force 1 were anxious and prepared to perform those difficult searches Saturday. Instead, the Utah crew was given a quick course on how to perform hoist operations in the helicopters provided by the National Guard and other training.

But task force commander Keith Bevan said the priority of all the available helicopters on Saturday was to find survivors.

"Our priority right now is if you have people who need to be removed from these areas, you spend all of your resource time getting them out. It's difficult to explain if you send someone up to search an area where you think there might be someone versus someone who is standing there waving you down," he said.

Some members of Utah Task Force 1 did see some action Saturday. Dr. Laura McClain is the Task Force's veterinarian. She was called to treat a Coonhound that was rescued along with its owners. The dog had suffered a deep cut in the flooding debris that needed attention.

The task force, part of the Utah Urban Search and Rescue Team, consists of firefighters and paramedics from the Unified Fire Authority, Salt Lake City Fire Department and Park City Fire District.

The estimated number of people still unaccounted for in the flooded areas of Colorado was estimated at between 180 and 200. Pelle stressed that doesn't necessarily mean they are all missing. But family members had not been able to get in contact with them, either because phone and Internet service in the area was down or access to the area was cut off.

In the city of Boulder, conditions were dry Friday afternoon and Saturday during the day, allowing water in some of the flooded areas to recede. But the damage to some homes, roads and bridges will take weeks and even months to clean up and repair, according to city officials.

"This is probably a 1-in-1,000-year, or even less likely, storm," Boulder Mayor Matt Applebaum said Saturday.

The city knew it was prone to possible flash flooding, and had been preparing for many years for such a possibility.

"It's difficult to plan for something of this magnitude that affects every single drainage in the entire city," Applebaum said.

The campus of the University of Colorado remained closed Saturday and the school's football game was even cancelled.

Boulder County officials late Saturday announced that an estimated 120 to 150 miles of road needed to be repaired along with 20 to 30 bridges. The county estimated it would cost approximately $150 million to do that, or 10 to 15 times their annual budget. The county said it was hoping for a lot of private and government assistance.

Pelle urged residents to be patient because the county was not going to go back to normal once the rain stops falling.

"Our normal has changed for awhile," he said. "This is a huge deal and it's going to take awhile to get back to normal."

Colorado Gov. John Hickenlooper, with members of the state's congressional delegation, went on two rescue missions with the National Guard Saturday afternoon. They witnessed areas where there was once a road, and now only a river, and saw communities that had become completely cut off from the rest of the world, including no water, phones or power.

But the group vowed before a small gathering at the Boulder Municipal Airport that Colorado will rebuild.

"We're going to come back and we're going rebuild better than it was before, and as a community, stronger," the governor said.

Red Cross officials estimated that 1,000 people — mostly flood victims — spent Friday night at one of the nine shelters set up around the state.

"I think the overriding feeling is shock right now. For many people, this past week has been the worst week of their lives. And to come to terms that a lot of possessions in their homes may be gone, a pet, or even a loved one, these are some of the most tumultuous times they can go through," said Red Cross spokesman Jim Rettew.

Ben Genzel, who lives in a ground floor apartment in South Boulder, was forced to spend the night at one of the shelters set up at the YMCA in Boulder.

"The whole building, on the ground floors, have to be gutted because they're filled with mud, and everything is saturated, and probably about 75 percent of my things are destroyed. I was trying to sort through them yesterday and I just got exhausted. I have to go back today and see before it starts to get moldy, he said.

In the area of Jamestown, Pelle said about 50 people were refusing to leave their homes. He planned to send a deputy who lives in that area by helicopter to make one final plea for them to leave, before more heavy rain hits the area.

"He'll explain we may not be able to come back for several days. If they pass today, we may not be able to help today or tomorrow," said Pelle.

"The problem with this event is it's affected every drainage, every road in the county. You know, it's a sinking feeling when you realize ... that someone who calls 911, we're not going to be able to help. That's a very difficult decision."